Pressure balance type floating body and installation method thereof

ABSTRACT

The present invention relates to the technical field of ships, and particularly relates to a pressure balance type floating body and an installation method thereof. The floating body includes water cabins, gas cabins, gas cabin inflation valves, underwater even pressure control systems, water cabin water supply systems and water cabin ventilating systems. The buoyant center of the floating body and the gravity center of the floating body are located on the same vertical line, and the position of the buoyant center of the floating body is higher than the position of the gravity center of the floating body. The gas cabin inflation valve is arranged on each gas cabin, and the gas cabin inflation valve is connected with each underwater even pressure control system. The water cabin water supply system and the water cabin ventilating system are arranged on each water cabin.

RELATED APPLICATIONS

This application is a United States National Stage Application filed under 35 U.S.C 371 of PCT Patent Application Serial No. PCT/CN2013/079280, filed Jul. 12, 2013, which further claims priority of PCT Patent Application Serial No PCT/CN2013/073378, filed Mar. 28, 2013, the disclosure of all of which are hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to the technical field of ships, and particularly relates to a pressure balance type floating body and an installation method thereof.

BACKGROUND OF THE INVENTION

As offshore oil and gas resource development equipment, a floating production storage and offloading device (FPSO) is widely applied to oil and gas development under various water depth conditions. For a deepwater floating production storage and offloading device (FPSO), the working position of an underwater floating body thereof is generally in deep water, and the exterior of the floating body bears a very large water pressure. To prevent the floating body structure from being damaged by the larger water pressure, pressure equivalent to the external water pressure must exist in the floating body. A traditional underwater floating body is designed based on a non-pressure resistant structure, the floating body structure is of the non-pressure resistant structure, and the pressure resistance is limited, therefore the non-pressure resistant underwater floating body can be safely and normally installed and work on the premise of bearing no larger pressure. In the traditional underwater floating body, the floating body is inflated to generate a larger pressure in the floating body so as to balance the external water pressure of the floating body, namely the internal pressure of the floating body is increased by inflation when the floating body is located at any underwater position to make the internal pressure of the floating body be equivalent to the external water pressure, so as to protect the structure of the floating body form being damaged by higher water pressure, and for the above reasons, the installation process of the traditional underwater floating body is relatively complicated. In an installation process of the traditional underwater floating body, with the continuous change of water depth, the internal pressure of the floating body needs to be continuously adjusted, and meanwhile the posture of the floating body needs to be continuously adjusted. That is, with the increase of the water depth, the external water pressure of the floating body increases continuously, and to prevent the floating body from bearing overlarge pressure, the floating body needs to be continuously inflated to increase the internal pressure of the floating body to balance the external water pressure. The pressure bearing capability of the floating body structure is limited, thus the inflation process of the floating body must be performed segment by segment, namely pressure and balance must be adjusted once whenever reaching a certain water level, for example, the working water depth of a certain underwater floating body is about 300 m, and if this operation is performed once every 5 m (set according to the pressure resistance of the floating body), then the operations of pressure adjustment and underwater posture adjustment of the floating body need to be performed for dozens of times in the entire installation process. Moreover, the installation process of the traditional underwater floating body is completed underwater by a control system under the help of an underwater operating system (ROV), thus the installation process is difficult to achieve. The existing pressure control system cannot continuously control pressure and fails to achieve real-time measurement and real-time control.

SUMMARY OF THE INVENTION

The technical problem to be solved in the present invention is to provide a pressure balance type floating body which can be continuously installed underwater at one step and can prevent the damage to the bulkheads of the floating body, and an installation method thereof.

To solve the above technical problem, the present invention provides a pressure balance type floating body, including water cabins, gas cabins, underwater even pressure control systems used for controlling the gas pressure in the floating body, gas cabin inflation valves, water cabin water supply systems and water cabin ventilating systems, wherein the water cabins and the sub-cabins are not communicated. The buoyant center of the floating body and the gravity center of the floating body are located on the same vertical line, and the position of the buoyant center of the floating body is higher than the position of the gravity center of the floating body. The water cabins and the gas cabins are arranged at the left and right sides of the floating body, and the buoyant force provided by the water cabins and the gas cabins at the left side of the floating body is equal to the buoyant force provided by the water cabins and the gas cabins at the right side of the floating body. The water cabins and the gas cabins are arranged at the front and back sides of the floating body, the buoyant force provided by the water cabins and the gas cabins at the front side of the floating body is larger than the buoyant force provided by the water cabins and the gas cabins at the back side of the floating body, or the buoyant force provided by the water cabins and the gas cabins at the back side of the floating body is larger than the buoyant force provided by the water cabins and the gas cabins at the front side of the floating body. The water cabin water supply system and the water cabin ventilating system are arranged on each water cabin; one gas cabin inflation valve is arranged on each gas cabin. The underwater even pressure control systems are connected with the gas cabins.

Further, the buoyant force provided by the water cabins and the gas cabins at the front side of the floating body is larger than the buoyant force provided by the water cabins and the gas cabins at the back side of the floating body, or the buoyant force provided by the water cabins and the gas cabins at the back side of the floating body is larger than the buoyant force provided by the water cabins and the gas cabins at the front side of the floating body, including: the number of the water cabins and the gas cabins at the front side of the floating body is larger than the number of the water cabins and the gas cabins at the back side of the floating body, or the number of the water cabins and the gas cabins at the back side of the floating body is larger than the number of the water cabins and the gas cabins at the front side of the floating body.

Further, the number of the underwater even pressure control systems is the same as the number of the gas cabin inflation valves, and one gas cabin inflation valve is connected with one underwater even pressure control system.

Further, each underwater even pressure control system includes a drive circuit, inflation equipment, a solenoid valve for controlling the opening and closing of the inflation equipment, a gas pressure sensor, a water pressure sensor and a second controller used for sending an inflation control instruction to the inflation equipment according to data collected by the gas pressure sensor and the water pressure sensor. The second controller is connected with the solenoid valve through the drive circuit. The solenoid valve is connected with the inflation equipment. The gas pressure sensor and the water pressure sensor are respectively connected with the second controller. The inflation equipment is connected with the gas cabin inflation valves.

Further, the second controller includes a data receiving module used for receiving the data collected by the gas pressure sensor and the water pressure sensor; a processing module used for sending a control instruction for controlling the opening and closing of the inflation equipment to the solenoid valve according to the data collected by the data receiving module.

Further, the processing module includes a judging unit used for judging whether the pressure in the gas cabins is consistent with the external water pressure according to the data collected by the data receiving module; an executing unit used for generating a control instruction indicating that a gas flow needs to be inflated to the gas cabins and sending the control instruction to the solenoid valve through the drive circuit to control the solenoid valve to be opened, when the judging unit judges that the pressure in the gas cabins is not consistent with the external water pressure; sending an instruction of controlling the solenoid valve to be closed to the solenoid valve through the drive circuit, when the judging unit judges that the pressure in the gas cabins is consistent with the external water pressure.

Further, the pressure balance type floating body further includes a posture monitoring system and a controller. The posture monitoring system, the ventilating systems and the water supply systems are respectively connected with the controller. The posture monitoring system is used for monitoring the position of the floating body and monitoring that the floating body is at a balanced state or an inclined state, and when the floating body is at the inclined state, the controller controls the ventilating systems to inflate the water cabins at the downward inclined end of the floating body until the floating body is not inclined any more.

Further, the posture monitoring system is composed of four position sensors. The four position sensors are respectively installed on the four corners on the surrounding of the floating body; the four position sensors are respectively connected with the controller.

Further, the water cabin ventilating systems are arranged at the top ends of the water cabins. The water cabin water supply systems are arranged at the bottom ends of the water cabins.

The present invention further provides an installation method of the pressure balance type floating body, including: filling the water cabins with water, starting each underwater even pressure control system to submerge the main body of the floating body until the main body of the floating body is completely submerged in the water; hauling the body of the floating body downwards by using an underwater hauling system, and controlling the gas pressure in each gas cabin to be consistent with the external water pressure through the underwater even pressure control system; after the body of the floating body arrives at a working water area, inflating each water cabin to discharge water in the water cabin so as to enable the water cabin to provide an upward positive buoyant force.

Further, the hauling the body of the floating body downwards, and controlling the gas pressure in each gas cabin to be consistent with the external water pressure through the underwater even pressure control system, includes: detecting the gas pressure in the gas cabin through the gas pressure sensor, detecting the external water pressure through the water pressure sensor, and transmitting the detection results of gas pressure and water pressure to the second controller. The second controller uses the pressure difference between the gas pressure and the water pressure as a control input parameter, judges whether the pressure in the gas cabin is consistent with the external water pressure, if being not consistent, the second controller generates a control instruction of determining the gas flow, transmits the control instruction to the drive circuit to be amplified and converted into a control signal and transmits the control signal to the solenoid valve, the solenoid valve is opened, and the inflation equipment inflates the gas cabin; if being consistent, the second controller stops sending the control instruction of determining the gas flow, the solenoid valve is closed, and the inflation equipment stops inflating the gas cabin.

Further, the after the body of the floating body arrives at a working water area, inflating each water cabin to discharge water in the water cabin so as to enable the water cabin to provide an upward positive buoyant force, includes: determining the necessary total displacement of the water cabins; determining the total inflation amount of the water cabins according to the necessary total displacement of the water cabins, averagely distributing the total inflation amount to all the water cabins, and determining the inflation amount of each water cabin; respectively inflating gas with corresponding inflation amounts in the water cabins through the water cabin ventilating systems; closing the ventilating system on each water cabin after each water cabin is inflated, so as to enable each water cabin to provide the upward positive buoyant force.

Further, the method further includes: after inflation, monitoring the position of the floating body via the four position sensors distributed on the four corners of the floating body, monitoring that the floating body is at the balanced state or the inclined state, and when the floating body is at the inclined state, controlling the ventilating systems through the controller to inflate the water cabins at the downward inclined end of the floating body until the floating body is not inclined any more.

According to the pressure balance type floating body provided by the present invention, the maximum buoyant force capable of being provided by the water cabins and the gas cabins arranged at the left side of the floating body is equal to the maximum buoyant force capable of being provided by the water cabins and the gas cabins arranged at the right side of the floating body, therefore the left and right sides of the floating body can be kept at an approximately stable state. The maximum buoyant force capable of being provided by the water cabins and the gas cabins arranged at the front side of the floating body is different from the maximum buoyant force capable of being provided by the water cabins and the gas cabins arranged at the back side of the floating body, therefore a deep sea pipeline can be loaded according to different gravities on different sides of the deep sea pipeline. Meanwhile, the position of the buoyant center of the floating body and the position of the gravity center of the floating body are located on the same vertical line, and the position of the buoyant center is higher than the position of the gravity center, so that the entire floating body can be kept at a stable state when at work. In a submerging process of the body of the floating body, the underwater even pressure control systems can inflate the gas cabins according to the external water pressure to make the pressure in the gas cabins be consistent with the external water pressure, so as to prevent the body of the floating body from being damaged by a larger external pressure, and the underwater even pressure control systems play a real-time measurement and real-time control role. The gas cabins provide an upward buoyant force so as to overcome the gravity of the body of the floating body itself to stably submerge the floating body. Since the resultant force of the upward buoyant force provided by the sub-cabins and the downward gravity of the floating body is smaller, the floating body is basically at the stable state, thereby reducing the force application strength of the hauling system on the floating body and reducing the requirements on the structural strength at the connecting sites with the hauling system the external cabins. After the body of the floating body is inflated in the working water area, the water cabins are inflated, and the water cabins provide the upward positive buoyant force to ensure the normal work of the underwater floating body.

According to the installation method of the underwater floating body provided by the present invention, the posture adjustment process is simple and controllable, and the floating body can arrive at a preset water depth at one step without being gradually adjusted during installation, thereby improving the installation efficiency and saving a large amount of manpower and material resources. In the entire submerging process of the floating body, the fine tuning of the posture is completely achieved by the hauling system, so that the adjustment is convenient. The operations in the entire installation process are completed by a water surface control system, and no underwater operation is carried out. Therefore, the floating body provided by the present invention can be installed without the help of an underwater operating system (ROV), so that the installation cost is greatly reduced and the installation controllability is stronger. After the floating body enters the working state, either the gas cabins or the water cabins nearly bear no pressure, thereby prolonging the service lives of the gas cabins and the water cabins.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a structure of the body of a floating body provided by an embodiment of the present invention.

FIG. 2 is a left view of FIG. 1 provided by the embodiment of the present invention.

FIG. 3 is a working schematic diagram of an underwater even pressure control system provided by the embodiment of the present invention.

FIG. 4 is a system block diagram of a second controller as shown in FIG. 3.

DETAILED DESCRIPTION OF THE EMBODIMENTS

See FIG. 1 to FIG. 4, the present invention provides a pressure balance type floating body, including the body of the floating body, gas cabin inflation valves, water cabin water supply systems, water cabin ventilating systems, a first controller, a posture monitoring system and underwater even pressure control systems used for controlling the gas pressure in the body of the floating body. The interior of the body of the floating body is divided into at least one water cabin 1 and at least one gas cabin 2, the water cabin 1 and the gas cabin 2 are merely two different types of cabins in the floating body, and the materials and the connecting manners of the two types of cabins should meet the requirements of good sealing property. At first, the structures of the water cabin 1 and the gas cabin 2 are described, the water cabin 1 and the gas cabin 2 are formed by welding plates with different specifications, specifically: plates with the same material and thickness are adopted, different plates are welded together to form a plurality of cabins, and the plates are high-strength and corrosion-resistant steel plates. All the cabins can be rectangles or squares, and all shapes meeting the design idea of the present invention are encompassed within the protection scope of the present invention. Each cabin is a relatively independent closed space, and in an actual manufacturing process, a plate with a larger area is used as the bottom plate of all the cabins. In the embodiment, all the cabins are arranged closely, two adjacent cabins share a bulkhead, all the cabins are distributed to form a square integral structure, the square integral structure formed by all the cabins is eudipleural, and the symmetrical arrangement of the cabins is an important means for keeping the balance of the entire floating body. In the embodiment, one row of cabins is respectively distributed on the front side, the left side and the right side of the square integral structure, one row of cabins is distributed on the back side (namely the B side in FIG. 1) of the square integral structure, one row of sub-cabins 1 is respectively distributed on the left side, the right side and the front side (namely the A side in FIG. 1) of the square integral structure, the maximum buoyant force capable of being provided by the water cabins 1 and the gas cabins 2 on the front side of the square entirety (namely the front side of the floating body) is larger than the maximum buoyant force capable of being provided by the water cabins 1 and the gas cabins 2 on the back side of the square entirety (namely the back side of the floating body), or the maximum buoyant force capable of being provided by the water cabins 1 and the gas cabins 2 on the back side of the square entirety (namely the back side of the floating body) is larger than the maximum buoyant force capable of being provided by the water cabins 1 and the gas cabins 2 on the front side of the square entirety (namely the front side of the floating body). In the embodiment, the buoyant force capable of being provided on the front side and the back side of the floating body can be determined according to the number of the water cabins and the gas cabins on the front side and the back side of the floating body, and for the water cabins or the gas cabins with the same specification, the larger the number is, the larger the provided buoyant force is. The eudipleural but fore-and-aft asymmetrical structures of the cabins are designed according to the application of the floating body, the floating body is mainly used for supporting a subsea oil pipeline, the oil pipeline extends all the way from the seabed to the sea surface, the oil pipeline extending from the seabed is fixed on the back end of the square entirety (namely the back end of the floating body) and extends to the sea surface through the front end of the square entirety (namely the front end of the floating body); since the length of the end of the oil pipeline extending from the seabed is larger than the length of the end extending to the sea surface, the weight of the end of the oil pipeline extending from the seabed is larger than the weight of the end extending to the sea surface; more cabins need to be designed on the back end of the square entirety to provide a larger buoyant force to bear the end with larger weight on the oil pipeline. All the cabins are divided into the water cabins 1 and the gas cabins 2, and the water cabins 1 and the gas cabins 2 are not communicated. In the embodiment, the square integral structure has 48 cabins in total, including 32 water cabins 1 and 16 gas cabins 2, the 32 water cabins 1 distributed on the square integral structure are eudipleural (namely the water cabins 1 distributed at the left and right sides of the center line of the square integral structure plane are symmetrical); the 16 gas cabins 2 distributed on the square integral structure are eudipleural (namely the gas cabins 2 distributed at the left and right sides of the center line of the square integral structure plane are symmetrical). The design solution of the gas cabins 2 and the water cabins 1 is specifically as follows: step S1: determining the total volume v of the gas cabins 2 according to the total weight G of the floating body (it is required that the gas cabins 2 can provide a necessary buoyant force in the submerging process of the floating body after being fully inflated, in order to make the buoyant force be basically equal to the value of the total weight G of the floating body); step S2: determining the total volume V of discharged water of the water cabins 1 according to the necessary positive buoyant force F of the floating body when at work, calculating the total displacement of the water cabins 1, and calculating the total inflation amount of the water cabins 1 according to the total displacement of the water cabins 1; S3: averagely distributing the total inflation amount of the water cabins 1 to each water cabin 1 to obtain the inflation amount of each water cabin 1; step S4: in a design process of the floating body, locating the buoyant center of the floating body and the gravity center of the floating body on the same vertical line, and making the buoyant center of the floating body be slightly higher than the gravity center of the floating body. It is set that the position of the buoyant center is (xB, yB, zB) and the position of the gravity center is (xG, yG, zG), therefore the position relationship of the gravity center and the buoyant center needs to satisfy: x_(G)=x_(B)=0,y_(G)=y_(B) and z_(B)≧z_(G)≧0. In a process of determining the buoyant center of the floating body and the gravity center of the floating body, the position of the buoyant center of the floating body is calculated at first, then the structures and sizes of the water cabins 1 and other facilities on the floating body are adjusted according to the position of the buoyant center to adjust the position of the gravity center, so as to locate the gravity center of the floating body and the buoyant center of the floating body on the same vertical line and make the buoyant center of the floating body be slightly higher than the gravity center of the floating body. It should be noted that, when calculating the coordinates of the gravity center, the weights of the water cabins 1, the gas cabins 2 and other facilities on the floating body need to be considered at the same time, namely the gravity center of the floating body is the gravity center of the entirety formed by the water cabins 1, the gas cabins 2 and other facilities on the floating body. One gas cabin inflation valve is arranged on each gas cabin 2, the number of the underwater even pressure control systems is the same as the number of the gas cabin inflation valves, and one underwater even pressure control system is connected with one gas cabin inflation valve. A water cabin water supply system is arranged at the bottom end of each water cabin 1, and a water cabin ventilating system is arranged at the top end of each water cabin 1. The water cabin water supply system is composed of two one-way valves, which are respectively a water inlet valve and a water outlet valve, the threshold of the one-way valve can be individually selected, when the difference between internal and external pressures of the water cabins exceeds the threshold, water is discharged from the cabins through the water outlet valve or enters the cabins through the water inlet valve. The water cabin ventilating system includes gas holes and gas pipes connected with the gas holes, the gas pipes are divided into two groups, one group of gas pipes is directly connected with the atmosphere and is matched with the water cabin water supply systems to achieve the water supply function of the water cabins, and the other group of gas pipes is connected with the inflation equipment for inflating the water cabins. The posture monitoring system is composed of four position sensors, the four position sensors are respectively distributed on the four corners on the surrounding of the floating body, the controller judges whether the floating body is at a balanced state or a certain inclined state according to position signals fed back by the four position sensors, monitors the posture information of the floating body and monitors that the floating body is at the balanced state or the inclined state. The posture monitoring system is connected with the first controller, and the first controller is connected with the ventilating systems and the water supply systems of the water cabins 1. The posture monitoring system monitors the position of the floating body and monitors that the floating body is at the balanced state or the inclined state, when the floating body is at the inclined state, the first controller judges which end of the floating body is inclined downwards according to the position information of the floating body obtained by the posture monitoring system and controls the ventilating systems to inflate the water cabins 1 at the downward inclined end until the floating body is not inclined any more.

See FIG. 3, the underwater even pressure control system includes a second controller for sending an inflation control instruction, a drive circuit, a solenoid valve, inflation equipment, a gas pressure sensor, a water pressure sensor and HMI equipment. The second controller is connected with the solenoid valve through the drive circuit. The solenoid valve is connected with the inflation equipment. The gas pressure sensor and the water pressure sensor are respectively connected with the second controller. The inflation equipment is connected with the gas cabin inflation valves. See FIG. 4, the second controller includes a data receiving module and a processing module; the data receiving module is used for receiving the data collected by the gas pressure sensor and the water pressure sensor; the processing module is used for sending a control instruction for controlling the opening and closing of the inflation equipment to the solenoid valve according to the data collected by the data receiving module. The processing module includes a judging unit and an executing unit. The judging unit is used for judging whether the pressure in the gas cabins is consistent with the external water pressure according to the data collected by the data receiving module. The executing unit is used for generating a control instruction indicating that a gas flow needs to be inflated to the gas cabins and sending the control instruction to the solenoid valve through the drive circuit to control the solenoid valve to be opened, when the judging unit judges that the pressure in the gas cabins is not consistent with the external water pressure; sending an instruction of controlling the solenoid valve to be closed to the solenoid valve through the drive circuit, when the judging unit judges that the pressure in the gas cabins is consistent with the external water pressure. The HMI equipment is external monitoring and input equipment, and the HMI equipment is connected with the second controller. A debugging module, a pressure display module, an alarm module and an equipment monitoring module are integrated in the HMI equipment. The debugging module, the pressure display module, the alarm module and the equipment monitoring module are software units and are “project files” edited by screen dynamic software on a computer, and these “project files” are downloaded to the HMI equipment to form different functional modules. The debugging module is used for debugging the floating body before submerging the same, the debugging module is used for sending an artificially set pressure difference value (namely the difference between the pressure in the gas cabin and the water pressure at the outside of the gas cabin) to the second controller, it is set in the embodiment that the water pressure at the outside of the gas cabin is larger than the gas pressure in the gas cabin by X MPa, the pressure difference value (X MPa) is transmitted to the second controller, if the inflation equipment inflates the gas cabin, and the reading of the pressure sensor is increased by X MPa, it indicates that the debugging is successful, and the underwater even pressure control system can work normally. The pressure display module is used for displaying pressure numerical values obtained by the gas pressure sensor and the water pressure sensor in real time, for facilitating observation and recording by a worker. The alarm module is used for monitoring the working state of the underwater even pressure control system, after the pressure difference between the gas pressure sensor and the water pressure sensor exists and the pressure difference does not disappear within 15 seconds (this time can be artificially set) but increases instead, it indicates that the underwater even pressure control system cannot work normally, and at this time, the alarm module alarms to prompt the worker to troubleshoot. The equipment monitoring module is used for monitoring the working states of the gas pressure sensor, the water pressure sensor, the second controller, the drive circuit and the solenoid valve, and in the case of failure of the monitored equipment, the equipment monitoring module displays the failed equipment and alarms through the alarm module.

The embodiment of the present invention further provides an installation method of the pressure balance type floating body, including:

step 10: filling the water cabins 1 with water, starting each underwater even pressure control system to submerge the main body of the floating body until the main body of the floating body is completely submerged in the water;

step 20: hauling the body of the floating body downwards, and controlling the gas pressure in each gas cabin 2 to be consistent with the external water pressure through the underwater even pressure control system, specifically: see FIG. 3, hauling the body of the floating body downwards through underwater hauling equipment, detecting the gas pressure in the gas cabin 2 through the gas pressure sensor, detecting the external water pressure through the water pressure sensor, and transmitting the detection results of gas pressure and water pressure to the second controller. The second controller uses the pressure difference between the gas pressure and the water pressure as a control input parameter, judges whether the pressure in the gas cabin is consistent with the external water pressure, if being not consistent, the second controller generates a control instruction of determining the gas flow, transmits the control instruction to the drive circuit to be amplified and converted into a control signal and transmits the control signal to the solenoid valve, the solenoid valve is opened, and the inflation equipment inflates the gas cabin 2. If the pressure in the gas cabin 2 is consistent with the external water pressure, the second controller stops sending the control instruction of determining the gas flow, the solenoid valve is closed, and the inflation equipment stops inflating the gas cabin 2;

step 30: after the body of the floating body arrives at a working water area, controlling the water cabin ventilating system through the first controller to inflate each water cabin 1 to discharge water in the water cabin 1 so as to enable the water cabin 1 to provide an upward positive buoyant force, specifically: determining the necessary total displacement of the water cabins 1 according to requirements of the body of the floating body on the positive buoyant force; calculating the total inflation amount of the water cabins 1 according to the total displacement of the water cabins 1 and a gas state equation, averagely distributing the total inflation amount of the water cabins 1 to the water cabins 1, and determining the inflation amounts of the water cabins 1; respectively inflating gas with corresponding inflation amounts in the water cabins 1 through the water cabin ventilating systems; after inflation, monitoring the position of the floating body via the posture monitoring system, monitoring that the floating body is at a balanced state or an inclined state, and when the floating body is at the inclined state, controlling the ventilating systems through the controller to inflate the water cabins 1 at the downward inclined end of the floating body until the floating body is not inclined any more. In the embodiment, the unit of total displacement is ton, the unit of displacement is ton, and the unit of the inflation amount is cubic meter.

The working principle of the floating body is analyzed and illustrated below: in the submerging process of the body of the floating body, the underwater even pressure control systems can inflate the gas cabins 2 according to the external water pressure to make the pressure in the gas cabins 2 be consistent with the external water pressure, at this time, the resultant force of all on the outer walls of the gas cabins 2 is basically zero, thereby preventing the body of the floating body from being damaged by the larger external pressure. The gas cabins 2 provide an upward buoyant force so as to overcome the gravity of the body of the floating body itself to stably submerge the floating body, and meanwhile reduce the force application strength of the hauling system on the floating body and reduce the requirements on the structural strength at the connecting sites with the hauling system the external cabins. After the body of the floating body is inflated in the working water area, the water cabins 1 are inflated, and the water cabins 1 provide the upward positive buoyant force to ensure the normal work of the underwater floating body. The buoyant center of the body of the floating body and the gravity center of the body of the floating body are located on the same vertical line, and the position of the buoyant center is higher than the position of the gravity center, so that the entire floating body can be kept at a balanced state in the submerging process due to this design principle. After the body of the floating body arrives at the working water area, the water cabins 1 are inflated to discharge a part of water in the water cabins 1, so that the weight of the discharged water is just equal to the positive buoyant force, in this way, the water cabins 1 can provide the positive buoyant force satisfying the working requirements. When the water cabins 1 of the body of the floating body are inflated to discharge water, the positions of the gravity center and the buoyant center of the body of the entire floating body are changed to influence the posture of the body of the floating body, and the displacement of each water cabin 1 can be controlled to control the positions of the gravity center and the buoyant center of the body of the floating body with water discharged, so as to guarantee the posture balance of the body of the floating body, specifically including: step 110. the necessary total displacement is determined according to requirements of the body of the floating body on the positive buoyant force; step 220. the total inflation amount of the water cabins 1 is calculated according to the total displacement of the water cabins 1 and the gas state equation, the total inflation amount of the water cabins 1 is averagely distributed to the water cabins 1, and the inflation amounts of the water cabins 1 are determined; step 110 and step 220 can be preset before submerging the floating body to ensure the submerging safety of the floating body; step 330. gas with corresponding inflation amounts are respectively filled in the water cabins 1 through the water cabin ventilating systems. The operation principle of water discharge by inflation is as follows: the gas pressure in the water cabins 1 is increased by inflation of the water cabin ventilating systems to be larger than the external water pressure, and water in the water cabins 1 can be automatically discharged through the water cabin water supply systems under the effect of pressure difference. After a part of water is discharged, the gas spaces in the water cabins 1 become larger, the gas pressure is reduced, when the gas pressure in the water cabins 1 is reduced to be smaller than the external water pressure, water will enter the water cabins 1 through the water cabin water supply systems to reduce the gas spaces in the water cabins 1 so as to increase the gas pressure. The above process is repeated to eventually reach a dynamic balance. Step 440. after the water cabins 1 are inflated, the four position sensors monitor the position of the floating body, the controller calculates according to position signals fed back by the four position sensors to obtain the posture angle of the floating body and judges whether the floating body is at a balanced state or a certain inclined state, when the floating body is at the inclined state, the controller judges which end of the floating body is inclined downwards according to the position information of the floating body obtained by the posture monitoring system and controls the ventilating systems to inflate the water cabins 1 at the downward inclined end until the floating body is not inclined any more.

The embodiment of the present invention has the following beneficial effects:

1. the maximum buoyant force capable of being provided by the water cabins and the gas cabins arranged at the left side of the floating body is equal to the maximum buoyant force capable of being provided by the water cabins and the gas cabins arranged at the right side of the floating body, therefore the left and right sides of the floating body can be kept at an approximately stable state. The maximum buoyant force capable of being provided by the water cabins and the gas cabins arranged at the front side of the floating body is different from the maximum buoyant force capable of being provided by the water cabins and the gas cabins arranged at the back side of the floating body, therefore a deep sea pipeline can be loaded according to different gravities on different sides of the deep sea pipeline. Meanwhile, the position of the buoyant center and the position of the gravity center of the floating body are located on the same vertical line, and the position of the buoyant center is higher than the position of the gravity center, so that the entire floating body can be kept at a stable state when at work. In a submerging process of the body of the floating body, the underwater even pressure control systems can inflate the gas cabins according to the external water pressure to make the pressure in the gas cabins be consistent with the external water pressure, so as to prevent the body of the floating body from being damaged by a larger external pressure.

2. The gas cabins provide an upward buoyant force so as to overcome the gravity of the body of the floating body itself to stably submerge the body of the floating body. Since the resultant force of the upward buoyant force provided by the sub-cabins and the downward gravity of the floating body is smaller, the floating body is basically at the stable state, thereby reducing the force application strength of the hauling system on the floating body and reducing the requirements on the structural strength at the connecting sites with the hauling system on the external cabins.

3. In the installation solution in the present invention, the posture adjustment process is simple and controllable, and the floating body can arrive at a preset water depth at one step without being gradually adjusted during installation, thereby improving the installation efficiency and saving a large amount of manpower and material resources.

4. In the entire submerging process of the floating body, no inflation or deflation operation is carried out, and the pressure in the floating body is always at a self-balancing state. Meanwhile, the fine tuning of the posture of the floating body in the entire submerging process is completely achieved by the hauling system, so that the adjustment is convenient.

5. The operations in the entire installation process are completed by a water surface control system, and no underwater operation is carried out. Therefore, the pressure balance type floating body provided by the present invention can be installed without the help of the underwater operating system (ROV), so that the installation cost is greatly reduced and the installation controllability is stronger.

6. After the floating body enters the working state, either the water cabins or the gas cabins nearly bear no pressure, thereby prolonging the service lives of the water cabins and the gas cabins.

Finally, it should be noted that, the foregoing specific implementations are merely used for illustrating the technical solutions of the present invention, rather than limiting, although the present invention has been described in detail with reference to examples, those of ordinary skill in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention, without departing from the spirit and scope of the technical solutions of the present invention, and these modifications or equivalent substitutions are encompassed within the scope of the claims of the present invention. 

1. A pressure balance type floating body, comprising water cabins, gas cabins, underwater even pressure control systems for controlling the gas pressure in the body of the floating body, gas cabin inflation valves, water cabin water supply systems and water cabin ventilating systems, wherein the water cabins and the gas cabins are not communicated; the buoyant center of the floating body and the gravity center of the floating body are located on the same vertical line, and the position of the buoyant center of the floating body is higher than the position of the gravity center of the floating body; the water cabins and the gas cabins are arranged at the left and right sides of the floating body, and the buoyant force provided by the water cabins and the gas cabins at the left side of the floating body is equal to the buoyant force provided by the water cabins and the gas cabins at the right side of the floating body; the water cabins and the gas cabins are arranged at the front and back sides of the floating body, the buoyant force provided by the water cabins and the gas cabins at the front side of the floating body is larger than the buoyant force provided by the water cabins and the gas cabins at the back side of the floating body, or the buoyant force provided by the water cabins and the gas cabins at the back side of the floating body is larger than the buoyant force provided by the water cabins and the gas cabins at the front side of the floating body; the water cabin water supply system and the water cabin ventilating system are arranged on each water cabin; one gas cabin inflation valve is arranged on each gas cabin; the underwater even pressure control systems are connected with the gas cabins.
 2. The pressure balance type floating body of claim 1, wherein the buoyant force provided by the water cabins and the gas cabins at the front side of the floating body is larger than the buoyant force provided by the water cabins and the gas cabins at the back side of the floating body, or the buoyant force provided by the water cabins and the gas cabins at the back side of the floating body is larger than the buoyant force provided by the water cabins and the gas cabins at the front side of the floating body, comprising: the number of the water cabins and the gas cabins at the front side of the floating body is larger than the number of the water cabins and the gas cabins at the back side of the floating body, or the number of the water cabins and the gas cabins at the back side of the floating body is larger than the number of the water cabins and the gas cabins at the front side of the floating body.
 3. The pressure balance type floating body of claim 2, wherein the number of the underwater even pressure control systems is the same as the number of the gas cabin inflation valves, and one gas cabin inflation valve is connected with one underwater even pressure control system.
 4. The pressure balance type floating body of claim 3, wherein each underwater even pressure control system comprises a drive circuit, inflation equipment, a solenoid valve for controlling the opening and closing of the inflation equipment, a gas pressure sensor, a water pressure sensor and a second controller used for sending an inflation control instruction to the inflation equipment according to data collected by the gas pressure sensor and the water pressure sensor; the second controller is connected with the solenoid valve through the drive circuit; the solenoid valve is connected with the inflation equipment; the gas pressure sensor and the water pressure sensor are respectively connected with the second controller; the inflation equipment is connected with the gas cabin inflation valves.
 5. The pressure balance type floating body of claim 4, wherein the second controller comprises: a data receiving module used for receiving the data collected by the gas pressure sensor and the water pressure sensor; a processing module used for sending a control instruction for controlling the opening and closing of the inflation equipment to the solenoid valve according to the data collected by the data receiving module.
 6. The pressure balance type floating body of claim 5, wherein the processing module comprises a judging unit used for judging whether the pressure in the gas cabins is consistent with the external water pressure according to the data collected by the data receiving module; an executing unit used for generating a control instruction indicating that a gas flow needs to be inflated to the gas cabins and sending the control instruction to the solenoid valve through the drive circuit to control the solenoid valve to be opened, when the judging unit judges that the pressure in the gas cabins is not consistent with the external water pressure; sending an instruction of controlling the solenoid valve to be closed to the solenoid valve through the drive circuit, when the judging unit judges that the pressure in the gas cabins is consistent with the external water pressure.
 7. The pressure balance type floating body of claim 6, further comprising a posture monitoring system and a controller, wherein the posture monitoring system, the ventilating systems and the water supply systems are respectively connected with the controller; the posture monitoring system is used for monitoring the position of the floating body and monitoring that the floating body is at a balanced state or an inclined state, and when the floating body is at the inclined state, the controller controls the ventilating systems to inflate the water cabins at the downward inclined end of the floating body until the floating body is not inclined any more.
 8. The pressure balance type floating body of claim 7, wherein the posture monitoring system is composed of four position sensors; the four position sensors are respectively installed on the four corners on the surrounding of the floating body; the four position sensors are respectively connected with the controller.
 9. The pressure balance type floating body of claim 8, wherein the water cabin ventilating systems are arranged at the top ends of the water cabins; the water cabin water supply systems are arranged at the bottom ends of the water cabins.
 10. An installation method of the pressure balance type floating body of claim 9, comprising: filling the water cabins with water, starting each underwater even pressure control system to submerge the main body of the floating body until the main body of the floating body is completely submerged in the water; hauling the body of the floating body downwards by using an underwater hauling system, and controlling the gas pressure in each gas cabin to be consistent with the external water pressure through the underwater even pressure control system; after the body of the floating body arrives at a working water area, inflating each water cabin to discharge water in the water cabin so as to enable the water cabin to provide an upward positive buoyant force.
 11. The installation method of the pressure balance type floating body of claim 10, wherein the hauling the body of the floating body downwards, and controlling the gas pressure in each gas cabin to be consistent with the external water pressure through the underwater even pressure control system, comprises: detecting the gas pressure in the gas cabin through the gas pressure sensor, detecting the external water pressure through the water pressure sensor, and transmitting the detection results of gas pressure and water pressure to the second controller; the second controller uses the pressure difference between the gas pressure and the water pressure as a control input parameter, judges whether the pressure in the gas cabin is consistent with the external water pressure, if being not consistent, the second controller generates a control instruction of determining the gas flow, transmits the control instruction to the drive circuit to be amplified and converted into a control signal and transmits the control signal to the solenoid valve, the solenoid valve is opened, and the inflation equipment inflates the gas cabin; if being consistent, the second controller stops sending the control instruction of determining the gas flow, the solenoid valve is closed, and the inflation equipment stops inflating the gas cabin.
 12. The installation method of the pressure balance type floating body of claim 11, wherein the after the body of the floating body arrives at a working water area, inflating each water cabin to discharge water in the water cabin so as to enable the water cabin to provide an upward positive buoyant force, comprises: determining the necessary total displacement of the water cabins; determining the total inflation amount of the water cabins according to the necessary total displacement of the water cabins, averagely distributing the total inflation amount to all the water cabins, and determining the inflation amount of each water cabin; respectively inflating gas with corresponding inflation amounts in the water cabins through the water cabin ventilating systems; closing the ventilating system on each water cabin after each water cabin is inflated, so as to enable each water cabin to provide the upward positive buoyant force.
 13. The installation method of the pressure balance type floating body of claim 12, further comprising: after inflation, monitoring the position of the floating body via the four position sensors distributed on the four corners of the floating body, monitoring that the floating body is at a balanced state or an inclined state, and when the floating body is at the inclined state, controlling the ventilating systems through the controller to inflate the water cabins at the downward inclined end of the floating body until the floating body is not inclined any more. 